Nail-shield.



J. M. THORP.

NAIL SHIELD. APPLICATION TILED JAN.14, 191s.

Patented Jan. 20, 1914.

INVENTOI L.

WITNEZ: 2 2%. (7

JAMES MADISON THORP, OF ALAMEDA, CALIFORNIA.

NAIL-SHIELD.

Specification of Letters Patent.

Patented Jan. 20, 1914.

Application filed January 14, 1913. Serial No. 741,969.

To all whom it may concern:

Be it known that I, Janus Manrson 'lnonr, a citizen of the United States, r esiding at Alameda, in the county of Alameda and State of California, have invented a new and useful Nail-Shield, of which the following is a specification.

My invention relates to nail shields for securing wood or other work to the surface of concrete or masonry walls. And the object is to provide means to secure said work in the most inexpensive manner both as to labor and material employed.

The methods now in general. use consist in; first, setting blocks of wood in the concrete forms, or molds, in such a manner that when the concrete is poured it will surround and grip the block on all sides except the face, and after the molds are stripped off this block is used to nail into to hold the woodwork; second, one method is to drill holes into the hardened concrete and drive a wooden plug therein to be used as the nailing block; third, woodwork is simply nailed to the concrete, trusting to said nails to puncture the mass and when successfully punctured to hold by friction; and fourth, for very heavy work holes are drilled into the concrete and expansive screws or bolts are used, but this method is far too expensive for ordinary use in light work. The first and second methods are costly especially where wages are high, as they involve considerable labor. The third method, while not so expensive when successful is made so by the number of failures to make the nail penetrate the concrete and on the whole is considered very poor work.

I attain the objects of my invention by means hereinafter described in these specifications and shown in the accompanying drawings in which similar numerals represent similar parts throughout the several views.

Figure 1 is the shield, the mold and concrete wall, all shown in section. Fig. 2 is a view of the wall in section, the shield is shown in full, with the end split open after the mold has been removed. Fig. 3 shows the wall and shield in longitudinal section and the split ends hammered flat against the surface of the concrete, also a section of a furring strip nailed to the wall by means of a common wire nail driven into the shield. Figs. at and 5 are end views of the shield as shown in Figs. 1 and 2; and Fig. 6 a section showing the shield. with slight corrugations to allow the concrete or mortar to cling more tightly.

(oncrete forms for walls as generally used consist of a hollow wall of inch boards into which the plastic concrete is poured, after setting for about ten days these forms are stripped off, leaving a wall of solid concrete. \Vhere interior plaster is to be applied di rectly to these walls it is customary to attach strips of wood to the concrete to act as a gage for the plaster and as a nailing strip for the finish woodwork, another custom is to fur the walls with strips to lath upon, in either case wood must be nailed to the concrete.

The object of my invention, as stated, is to prepare nailing facilities for the above mentioned strips, together with any other wood or metal work required to be fastened to the concrete.

The shield comprising my invention consists of a flat metal strip shaped to form the tube or hollow wire 1, which is slightly smaller in internal diameter than the nail 2 to be driven into it, the edges of said strip abutting so as to leave an unattached seam 3 along one side. The tube is cut into the desired lengths and pointed at one end 4:, leaving the other end square cut as at 5, the purpose of which is hereinafter explained. After the concrete forms (5 are completed and before they are filled the carpenter ascertains along what lines the desired nailings will occur, he then drives these head loss shields into the boards composing the forms until the square ends are flush with the boards as at 5 Fig. 1. After the necessary shields are all in, the concrete 7 is poured into the forms tightly embedding the shield therein. hen the necessary time has elapsed to harden the wall the forms are stripped off, the absence of heads on the shields allow this to be done easily. When ready to nail on the furring or grounds a cold-chisel is used to split the projecting end of the shield as at 8, Figs. 2 and 5, the lips are then hammered down as shown at 9 Fig. After which the furring strip 11 is placed over the shield and the nail 10 is driven. Owing to the nail being a little full in diameter and the tube being tightly embedded a slight expansion only will take place in the tube, thus the friction is great enough to tightly hold the nail.

I have hereinbefore described the use of the shield in concrete only, it is obvious, however, that it may be used in the joints of masonry while the mortar is soft, and after standing until the mortar becomes hard may be treated the same as for concrete.

A shield to be used for masonry where no forms are t6 be stripped oil may be made with an annular head if desired, also with corrugated sides to more firmly cling to the mortar as shown at 12 Fig. 6.

I have shown the shield as circular in cross section, a smooth exterior and with a pointed end to facilitate driving, it is obvious, however, that a shield of any other form of cross section and wit-h any form of closed end to prevent the concrete from filling the tube may be used without departing from the spirit of my invention.

Having thus clearly described my inven tion, what I claim as new and desire tosecure by Letters Patent is 1. In a nail shield, a ribbon of metal folded along its length with abutting unwelded edges to form a tube, said tube being square cutintoshort lengths corresponding to the length of a nail to be driven therein, said short lengths of tube being swaged to a point on one end, the resulting hollow and headless nail being adapted to driving through the wall of a concrete form and protrude therein so as to be cast within the completed concrete wall, substantially as shown and described.

2. A nail shield or hollow nail, composed of a metal strip folded longitudinally to form a tube with abutting edges, one end of said tube being closed by swaging the metal to form a. point, the other end being open and headless and adapted to being split a portion of its length, substantially as described.

3. In a nail shield, a metal ribbon folded along its length to form a tube, the edges of said tube abutting su'liiciently close to prevent cement from flowing between said edges into the bore of the tube, one end o-fsaid tube being swaged to a solid point adaptable to driving through wood, said shield being adapted to receive and hold a nail by friction upon its interior wall and of being embedded in and gripped by a concrete mass, the outer end of said tube being headless and adapted to being split a portion of its length and the halves folded back at approximately ninety degrees, all as shown and described.

JAlslES MADISON THORP.

lVit-nesses VnnNoR E. T110121 F. It. NEVILLE.

Copies of this patent may be obtained. for five cents each, by addressing the Commissioner of Patents. Washington, I). C. 

